Solid inclusions

Spinel group minerals (Sources A, B, and C) [AB2O4 with A = Mg, Fe, Mn, Zn and B = Al, Mg, Fe2+, Fe3+, Cr,V ]

Botryoidal accumulation of F-phlogopite platelets accompanied by individual calcite crystals. 66x

Spinel occurs in material from all different sources. The chemical compositions are found to range from those of pure spinel (MgAl2O4), to green spinel with minor components of hercynite (FeAl2O4) and black spinels of mixed compositions of the gahnite(ZnAl2O4)-spinel-hercynite solid solution series. Further detailed microprobe analyses to establish the exact quantitative chemical characterization of these phases were not performed.